The present invention relates to an athletic shoe midsole design and construction. More particularly, the invention relates to a midsole assembly comprising a midsole formed of soft elastic material and a corrugated sheet disposed in the midsole.
The sole of an athletic shoe used in various sports is generally comprised of a midsole and an outsole. The midsole is typically formed of soft elastic material in order to ensure adequate cushioning properties. The outsole is fitted under the midsole and directly contacts with the ground.
Running stability as well as adequate cushioning properties are required in athletic shoes. Consequently, there is a need to prevent shoes from being deformed excessively in the lateral or transverse direction when contacting the ground.
As shown in Japanese Utility Model Examined Publication No. 61-6804, the assignee of the present invention proposes a midsole assembly having a corrugated sheet therein, which can prevent such an excessive lateral deformation of shoes and particularly shoe soles.
The midsole assembly shown in the above publication incorporates a corrugated sheet in the heel portion of a midsole, thereby producing a resistant force that prevents the heel portion of a midsole from being deformed laterally or transversely when a shoe contacts with the ground. Thus, transverse deformation of the heel portion of a shoe is prevented and running stability can be ensured.
Generally, by inserting a corrugated sheet, the heel portion of a midsole tends to be less deformed in the transverse direction and running stability can be improved. However, when the corrugated sheet is formed especially of high elastic material the heel portion of a midsole tends to be less deformed in the vertical direction as well. Thus, by using a corrugated sheet, a portion of the sale of where adequate cushioning properties are required on landing may show undesirably diminished cushioning properties.
The object of the present invention is to provide a midsole assembly for an athletic shoe that can ensure not only running stability but also cushioning properties.